A home security system may operate in two modes that may be generally referred to as an “away” mode or a “home” mode. The home security system may operate in an “away” mode, for example, when the occupants of the home are away for a period of time no more than 24 hours at a time (e.g., at work during the day). While operating in the away mode, the entry points for the home may be monitored for intrusion. A “home” mode may refer to the home security system's state when the occupants are home. For example, it may detect motion utilizing passive infrared sensors and activate interior lights in response thereto. The home security system may ignore a window or door being opened (or in any event, not trigger an intrusion alarm) while in the home mode. Thus, the mode of the home security system can affect the actions taken by the home security system in response to sensed activities in the home. While a user can manually program the timing of home and away states, the home security system may not automatically determine when a user is away from the home for an extended period of time such as on a long work trip or a vacation.